IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP6
Li3PO4:N/LiCoO2 Coatings for Thin Film Batteries

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Multilayers and Thin Film Characterization Poster Session
Presenter: M.E. Gross, Pacific Northwest National Laboratory
Authors: M.E. Gross, Pacific Northwest National Laboratory
P.M. Martin, Pacific Northwest National Laboratory
D.C. Stewart, Pacific Northwest National Laboratory
J.W. Johnston, Pacific Northwest National Laboratory
C.F. Windisch, Pacific Northwest National Laboratory
G.L. Graff, Pacific Northwest National Laboratory
P.L. Rissmiller, Mine Safety Appliances Company
E.L. Dudeck, Mine Safety Appliances Company
Correspondent: Click to Email
Li@sub 3@PO@sub 4@:N/Li@sub 1.04@CoO@sub 2@ thin film battery structures were deposited by reactive RF magnetron sputtering. Li@sub 3@PO@sub 4@:N (LIPON) thin films up to 1 µm thick were deposited using a 6" diameter Li@sub 2.9@PO@sub 3.5@ pressed powder target. Li@sub 1.04@CoO@sub 2@ thin films were deposited using a 6" diameter LiCoO@sub 2@ pressed powder target. LIPON films were deposited in He + N@sub2@ mixtures and LiCoO@sub 2@ films were deposited in Ar + O@sub 2@ mixtures. Total chamber pressure during deposition ranged between 10 and 20 mTorr and RF power to the sputtering targets ranged from 100 W to 400 W. Because XPS gave ambiguous compositional results, the films were optimized for AC and DC conductivity. Electrical conductivity was extremely sensitive to deposition conditions (deposition rate, sputtering gas pressure, and reactive gas partial pressure). AC conductivity measurements were made at a frequency of 10 kHz, and were correlated to DC conductivity measurements. LIPON films had highest conductivities in the 130 S.cm@super -1@ range and the highest AC conductivity of Li@sub 1.04@CoO@sub 2@ films was near 0.24 S.cm@super -1@. The most conductive films were deposited at 20 mTorr pressures and 100 W target power. X-ray diffraction analysis showed that the films were mostly amorphous. Films deposited under these conditions were transparent at visible wavelengths with a refractive index of 1.6. Lower conductivity films were brownish in appearance and less transmissive than films with high conductivity. The rechargeable battery structures consisting of a gold cathode, 0.4 µm LIPON, 0.6 µm Li@sub 1.04@CoO@sub2@, Li metal anode, and Cu substrate are currently under test. The thin film batteries have been cycled successfully. Performance results are correlated with film properties and reported. Future work will involve optimization of battery performance on a large scale and scale up of the deposition process.